Such a method is used in the field of automation technology where, as well as cable-linked components, those with a wireless communication connection are also used for control of the automation system. Components such as sensors and actuators for example are connected to a controller (abbreviated below to PLC) via central or local I/O modules. For cable-linked sensors (e.g. IO link . . . ) this connection takes the form of central periphery (e.g. digital modules in the rack of the PLC or integrated into the PLC. i.e. central peripheral submodules) or local peripherals (e.g. external digital modules). Connection as central periphery to the PLC is typically via proprietary mechanisms such as a proprietary backplane bus with proprietary protocol for example. Connection as local peripherals is typically undertaken using an IEC61158-standard field bus such as PROFINET IO, PROFIBUS DP, Interbus, CAN and their derivatives, Ethernet/IP, Ethercat . . . .
For wireless components (such as wireless HART or others) this linkage described above is developed correspondingly. Wireless sensors/actuators are also linked to the PLC as centrally or locally embodied links. Such a link is embodied for the PLC as periphery; it serves the wireless sensors/actuators as a wireless access point.
Wireless sensors/actuators are however—by contrast with cabled components—far more “mobile”, i.e. they can potentially roam through the installation. This roaming through the installation causes them to pass through several radio cells since a radio cell spanned by a link has a maximum geographical extent. Each radio cell is covered by an access point. The transfer to the next access point is supported by handover.
Handover is transparent to current wireless applications (for example making calls on a cell phone). If one of the parties to the call is moving out of the radio cell that they are currently using, the cell phone will automatically be transferred to the next cell (handover); the calling party and the called party do not notice this at all.
If wireless (mobile) components such as sensors/actuators use handover, the component is automatically handed over when roaming by the underlying wireless network protocol from access point to access point if it leaves a radio cell spanned by one access point and enters a radio cell spanned by another access point. It is assumed in this case that the component is handed over uniquely from access point to access point, i.e. is always assigned to precisely one access point. This is done by the underlying wireless network protocol.
Since the mobile component considered appears at different links (the link is thus the access point in relation to the component), but the link is linked in the upwards direction as central or local periphery to the PLC, this can be achieved with today's linkage mechanisms only in the following way:                The component must be planned in at all links which cover the roaming area of the component.        Each of the links reserves an explicit address area in the periphery data of the controller.        The handover of a component leads to diagnostic messages such as                    Component failure at old link and            Component restoration at new link                        After handover of the component its values appear at other locations in the periphery data.        
This means that an application running on the automation system must evaluate the diagnostic messages and control access to the corresponding address area in the periphery data in order to arrive at the data of the component. This leads to very complex applications.